In order to explore whether the damage caused by rotor drop can be reduced in case of the failure of magnetic bearing，the herringbone groove radial dynamic pressure gas bearing was introduced into the magnetic bearing rotor system，and the influence of the magnetic-gas bearing on the dynamic performance of the system and the support characteristics of the dynamic pressure gas bearing were studied.The finite difference method and small disturbance method were used to solve the film thickness equation and Reynolds equation，and the static and dynamic characteristics of the dynamic pressure gas bearing were studied.The electromagnetic force of the magnetic bearing was analyzed.The incomplete differential PID （proportion integration differentiation） control strategy of the magnetic bearing was used.The theoretical and test modal analysis of the system was performed.The high-speed rotation test of the system was completed.The bearing capacity of dynamic pressure gas bearing under different eccentricity and rotating speed was tested.Results showed that introduction of dynamic pressure gas bearings can improve the dynamic performance of the system.At the moment when the high-speed rotor dropped due to the failure of the magnetic bearing，the eccentricity was close to 1.The two radial dynamic pressure gas bearings can produce larger bearing capacity and reduce the drop caused by the rotor damage.